A judge has ordered a Waltham man charged with fatally stabbing his girlfriend to submit a DNA sample.

The Middlesex Superior Court judge approved collection of a saliva sample from Jared Remy at a hearing on Wednesday, according to Wicked Local news partner WCVB.

Remy, the 35-year-old son of Red Sox broadcaster Jerry Remy, has been charged with murder in the death of his girlfriend Jennifer Martel at their Waltham apartment on Aug. 15. He has pleaded not guilty.

Remy did not attend Wednesday's hearing.

The judge also approved an order from prosecutors and approved by Remy's attorney to seal from the public an interview that investigators conducted with the couple's then-4-year-old daughter a day after the slaying, according to WCVB. The girl was at the home at the time of the killing.